There
have been several times when I've wished for a toolpost grinder to finish
a shaft just right and to close tolerances. I debate whether to buy a
used Dumore or Themac on eBay or try to fabricate one as a project. Simple
ones are really easy to make and just involve lashing a suitable Dremel
or hand grinder to the post in some way. More complex versions involve
fabricating a spindle and replicating the style of the commercial TP grinders.
I am really tempted to work on a spindle for one. It would be a good warmup
should I ever choose to make a more ambitious spindle, perhaps for a lathe
or a mill. Meanwhile, I am collecting photos of TP Grinders others have
made for ideas.

Several designs ranging
from simple to fancier are pictured below:

This
is a very slick example using an air grinder and QCTP adapter...

Router-based
TP Grinder: A Bit Heavier Duty!

Router-based
TP Grinder Again...

Sewing
Machine Motor TP Grinder...

TP Grinder
from a Makita Trim Router...

A
TPG with a slightly larger die grinder. Note the cam action atop
for turning on the grinder...